Classic Parker Contest #1

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FOUNDER of Classic Parker Forum
Feb 16, 2006
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Newbury, MA
My OB Rebuild - best boating $$ I ever spent! Kevin's recent post (1 a day?) reminded me to post this ...

I have put 9 hours so far on my OB rebuild, after I put a hole in a piston :( (ID'd as a casting defect ...). I have to put 10 hours on her before I can set the final timing, stop the double-oiling (boy she smokes like Courtney Love at a metal concert :shock: when she starts!), and re-torque all the powerhead fasteners. I have survived the E10 fuel change so far too :) .

Best $$ I ever spent on a boat, this rebuild, the performance is A W E S O M E ! De-tuned (intentionally retarded ... the timing that is - not me ;) ) to turn only 5200 RPMs, she'll still push my Pahkah (that's Boston for "Parker" by the way) to 40 MPH ... imagine the top end when I wind her up to 5700 RPMs after an appointment with a test wheel :D ! My new and current prop is a cupped performance offshore SST model 3-blade stainless 15"x17" by OMC. This beats by far the old stock OMC and Michigan 15x17 props I tried last year. Performance props DO make a difference, as do new pistons and rings I guess.

At 4000 RPMs and with the tide I'm getting 26 knots, 30 MPH, for better than 2.5 miles per gallon.
At 4800 RPMs I'm getting 32 knots, 37 MPH, for 2.0+ miles per gallon.
At 5200 RPMs I'm getting 35 knots, 40 MPH, for ~1.7 miles per gallon.

I'll take that :D ! I'll drop a couple MPH when going against a stiff tide, but note that the MPG doesn't drop as much ... or maybe it does, like a 10% drop off of each across the board ... I haven't run the math!

I will provide FULL specs and prop slip calculations after I re-time her and put some RPMs through the OMC test prop. This test is wild in case you've never witnessed one. You tie her down to the dock tight, replace the prop with a test wheel (which looks like a tug prop, i.e., a ringed or caged propeller) and then add a timing light and fire her up to at least 5K RPMs. The rooster tail exiting the test prop would douse any fire within 50' ... there's really not too much forward torque per se, but the spray created is indeed impressive :shock: !

I learned a lot through the process and I will say, when you punch the throttle and she jumps up on plane ... pure wood ... and I sure don't mean teak!


Guess the final WOT speed in MPH, without going over (to the 1st decimal place, e.g., 43.3 or 45.1, etc.) and the winner gets a classic CP polo shirt in the size of their choice. Please enter only once and NO editing of your value is allowed. The decision of the CP Site Administrator is final and binding and ... yada yada ... yawn ... the rest has been deleted to protect the innocent.
sorry for the delay in the results ...

This should be resolved this WED ... had to wait for my mechanic to be free enough to schedule an on-the-water appointment to set the final timing, plus we also wanted to wait for cooler temperatures than the > 95 humid days we had in July.
DaleH":1cesye7w said:

Guess the final WOT speed in MPH, without going over (to the 1st decimal place, e.g., 43.3 or 45.1, etc.) and the winner gets a classic CP polo shirt in the size of their choice ...

Final Results:

No winners :( ... and clearly not me either ;) . Final speed in MPH, run both ways at top of the high tide slack was only 35.5 knots or 40.8 MPH. No winners, as the rules were "without going over" ... sorry, every one guessed higher! The lowest speed guessed was 41.4 MPH by our own esteemed prolific-Parker-poster Capt Kevin, aka "Megabyte". That final speed was run with the same 17" prop I was wearing before & after the rebuild.

The results were tested after the re-timing was advanced to 18-degrees before to-dead-center (TDC), which surprised me that the RPMs increase didn't turn up the speed more. Well, after re-checking everything, including the linkages and another 'sync & link' check, it turns out I was probably wearing the "wrong" wheel. To get my RPMs up past 5600 and closer to 5800 RPMs, I had to drop to a 15" pitch prop and thus I bought a 3-blade premium Stiletto from Dan's Discount Props (, costing only $230 and I got it in only 3-days :) . Shipping was $14.

FYI Overton's lets you exchange the Stilettos purchased from them, but they charge > $300. I could have sworn the factory prop was the 17" pitch wheel, but I will add ... my boat has lots of weight with the teak galley et al, plus all the fishing gear she carries, and ... the Stiletto prop has some serious cupping, which is akin to adding extra pitch to a blade. The 17" was a stock Michigan wheel, SS, but probably not as much a performance prop as the Stiletto.

So .. after my 225hp rebuild, I have no real complaints other than the price per gallon of fuel :shock: ! I may need to raise my OB one more bolt hole, but my performance now is ~38MPH with a dirty bottom, 1/2 fuel, full gear load, 2 guys, and while running E10 fuel. I put 80 miles on the other day, most of it waaaaaaaaaaaay offshore in some large seas (swells), including 4 hours of toona trolling, and I averaged 1.8 statute miles-per-gallon for the entire trip. Now a new technology DFI 2-stroke or newer 4-stroke would raise that MPG efficiency about 40% or so I am advised. Hmmmmmmmmm, go for a 300hp Suzuki 4-stroke or a 250hp E-Tec, or wait for the 300hp E-Tec :?: ?

Decisions, decisions ... but ... in reality, I don't think these mod-V 25' hulls need much more horsepower ... you?? As is, when offshore, I had to bury the nose (using tabs only on 1 side [increases MPG :) ]) and I could NOT have run any faster even if I had more ponies behind me. The only thing a new ~250hp OB would give me is better economy, besides the advantage of being "new". All around though, I'm thrilled with the rebuild and am glad I did the wrench work myself, having saved $2k+.